July 21 marks what would've been Robin Williams's 67th birthday, and his 28-year-old daughter, Zelda, is still coping with the heartbreaking loss. On Thursday, Zelda posted an old photo on Instagram of her and her dad, along with an emotional tribute. "Everyone who has dealt with loss knows the pain of certain anniversaries, moments full of memory that come round like clockwork and usurp all others," she wrote. "Thank you for loving...